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TRANSCRIPT
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Homework Solutions
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Geometry CP, May 3
Circles: Inscribed Angles and Tangents
Book Section: 10-4 & 10-5
Essential Question: What are inscribed angles in circles, circle tangents
and how can they be used?
Standards: G-5.1, .4, .5; CCSS C.GMD.1, .3; G-C.2, .5
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Definitions
• Inscribed angle – an angle that has a vertex on the
circle and sides that are chords of the circle.
• Intercepted arc – an arc with endpoints on the side of an
inscribed angle and lies in the interior of the inscribed
angle.
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How?
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Inscribed Angle Theorem
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Example 1 Use Inscribed Angles to Find Measures
A. Find mX.
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Example 1 Use Inscribed Angles to Find Measures
B.
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In a World of Equals
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Example 2 Use Inscribed Angles to Find Measures
ALGEBRA Find mR.
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Triangles – In a Circular World
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Example 4 Find Angle Measures in Inscribed Triangles
ALGEBRA Find mB.
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Quadrilaterals, Too?
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Example 5 Find Angle Measures
INSIGNIAS An insignia is an emblem that signifies rank, achievement, membership, and so on. The insignia shown is a quadrilateral inscribed in a circle. Find mS and mT.
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More Definitions
• Tangent – a line in the same plane as a circle that
intersects the circle at exactly one point, called the
point of tangency.
• Common tangent – a line, ray, or segment that is
tangent to two circles.
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Some Tangent Theory
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Example 6 Identify a Tangent
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More Equality (or Congruence)
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Example 7 Use Congruent Tangents to Find Measures
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One More Definition
• Circumscribed polygon – a polygon is circumscribed
about a circle if every side of the polygon is tangent to
the circle.
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Example 8 Find Measures in Circumscribed
Polygons
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Examples
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Classwork: Textbook p.727, 2-12 even;
p.736, 4-16 even
Homework: HW Due 5/7, All (both sides)